The purpose of this article is to examine the stability of a robust an
d decentralized PD control law for robot manipulator control. The cont
rol law, which was developed by the authors, has been shown experiment
ally to be extremely simple to implement and highly accurate for posit
ion and force tracking in the presence of robot model uncertainty and
payload variation. However, stability analysis has been difficult due
to the nonlinearity of robot dynamics and the use of time-delayed meas
urements of joint torques and joint accelerations in the control law.
A rigorous stability analysis is presented in this article using Popov
's hyperstability theory. A sufficient condition for global stability
is obtained that supports previous theoretical and experimental result
s. (C) 1996 John Wiley & Sons, Inc.